This Oulet boundary set must then be selected.  Upon selecting a pair of Inlet/Outlet Boundary Sets,  a menu appears that allows one to define the transformation matrix from the coordinates along the Inlet towards the Coordinates along the Outlet.  This tranformation matrix,  once applied to the coordinates of a node along the Inlet (and possibly adding the translation vector),  will produce the coordinates of the correspondant node along the outlet.  This matrix and this translation vector can either be entered in component form,  or be computed by giving two pairs of points which need to be put in correspondance.

For the energy equation,  continuity of the temperature together with flux continuity will be applied between Inlet and Outlet regions.

For the momentum equation,  the velocity profile will be continuous between the Inlet and the Outlet,  but a difference of normal force (of pressure) will be allowed between the inlet and the outlet.

This new variable,  the difference of normal force (or pressure),  will either be prescribed  (Normal Force Imposed),  or will be associated to new flow rate equation,  in which case the flow rate crossing those boundary sets must be prescribed as well (Flow Rate Imposed).

Automatically,  the Boundary Set that has been identified as an "Outlet" will be named accordingly in the summary of the boundary conditions